Grouplet
A grouplet is a small set of related meteorites, usually fewer than five, too few to define a formal group.
In meteorite classification, a group needs at least five unpaired members that share chemistry, oxygen isotopes and mineralogy. When only two to four related meteorites are known, they form a grouplet.
Grouplets often exist in the iron and achondrite classes and among unusual chondrites. Examples include the Kakangari chondrites, some small sets of iron meteorites with similar trace-element chemistry, and small clusters of carbonaceous chondrites that do not fit existing groups. As more meteorites are recovered, a grouplet may gain members and be promoted to a full group, as happened with several iron groups during the twentieth century.
The distinction matters because a group implies a single parent body with some understood history, while a grouplet is more tentative. A meteorite that matches no group or grouplet is called ungrouped. Paired fragments of the same fall are counted only once, so a grouplet must contain genuinely separate meteorites.
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